Remarkable progress has been made over the last decade on ventricular assist devices for adult heart failure patients. Thousands of patients' lives have been saved each year. Unfortunately, similar devices are not yet available in the US for pediatric heart patients. Development of such devices has been impeded by the fact that the pediatric market size is too small to attract interest from medical device companies. This Phase II study is a part of a National Institutes of Health effort of encouraging industry to develop such devices for an underserved but high-benefit population - pediatric heart patients. The goal of this project is to further develop a pediatric percutaneous ventricular assist device (pVAD) based on the existing adult TandemHeart(tm) pVAD System developed and currently marketed by our company, CardiacAssist, Inc. In the Phase I study, feasibility of such a device for pediatric application was successfully demonstrated on the bench top. Phase II study will focus on development of complete clinical prototypes and animal testing. Specifically, a spectrum of different sized cannulae will be developed to serve pediatric patients of all ages, from neonates (> 2 kg) to young adults. State of the art computational fluid dynamic and fluid visualization techniques will be used to design a safer and more effective blood pump for this pediatric application to reduce the levels of hemolysis. Safety and functionality of the developed system will be demonstrated in animal models. Upon successful completion of Phase II, CardiacAssist will undertake the final design and commercialization phase to introduce this device into the market. The proposed pediatric pVAD system is the only one in the field that can be placed percutaneously and serve pediatric patients of all sizes. Because it is inserted percutaneously, cardiac assistance can be provided quickly and less invasively, minimizing potential complications and promoting quicker patient recovery. Successful commercialization of this device will bring a unique tool to pediatric cardiologists and surgeons for their use in saving children's lives.